In Amsterdam “Het Breed” the renovation of 11 housing blocks (1,176 dwellings) began in May 2008. They had been built between 1963 and 1967 and now are getting new insulation at roof and floor, new double glazing in the façade and replacement of the building services.
Space heating and domestic hot water for the 11 buildings is produced in four boiler houses. The old gas boilers are replaced by new high efficiency gas boilers (Picture 1) that generate energy mainly for space heating. In two boiler houses, in total 20 gas absorption heat pumps (700 kW total) complement the heat generation of the gas boilers.
Solar thermal collectors (Picture 2 + 3), newly installed on the roofs of the buildings, deliver the heat for the domestic hot water. Space heating and domestic hot water are transported to the flats via separate small local district heating networks. All central heating pipes and water pipes in the ceilings of the buildings’ galleries have been replaced and well insulated.
After the refurbishment of the flats, the use of low temperature heating (65 °C instead of 90 °C) brings CO₂-emissions further down.
Furthermore, 217.5 kWp photovoltaic systems have been installed on the building blocks of Het Breed in December 2012.

In Het Breed, Amsterdam Noord, heat for heating and domestic hot water is generated in four boiler houses and distributed to the 1,176 dwellings of Het Breed via separated heating and domestic hot water networks. The boiler houses contain gas-fired high efficiency boilers (in total 8.9 MW), 20 gas absorption heat pumps (in total 0.7 MW) and large buffer storages for the hot water. These short-term buffer storages are filled with hot water provided by the 4 solar thermal plants on the roof of the buildings nearest to the boiler houses. The total area of the flat plate collectors is 1,230 m² (area of 251 m², 301.2 m², 326.6 m² and 351.4 m²) delivering heat for the domestic hot water. Due to the stochastic nature of solar radiation and its periodical availability, storages for the solar energy are necessary and were installed in the system. The domestic hot water system requires technically relatively simple storage units, though they have to be well insulated to minimize heat losses. In Het Breed, a total storage volume of 56,700 litres has been installed and provides the inhabitants of Het Breed with eco-friendly generated domestic hot water. In case the stored solar energy is insufficient to cover the demand, the gas-fired boilers supply the heat for the heating and contribute to the domestic hot water network.
All central heating pipes (Picture 4) and water pipes in the ceilings of the galleries (Picture 5) have been replaced and insulated. Figure 3 shows the location of the four boiler houses and in blue the new energy distribution network.
The monitoring results of the second year present a 20% reduction of energy consumption through the refurbishment of boiler houses and a new energy distribution system (Figure 4, retrofitted boiler house 4 compared to the at that time unchanged other boiler houses).
The dwelling-related measures like insulating the roof, renewing and extending the radiators in the flats, replacing the glazing etc. started after 70% of the tenants approved the refurbishment in February 2013. According to the planning, every week 10 dwellings will be delivered.

Figure 3 – Location of boiler houses and new energy distribution (blue lines)

Figure 4 – First monitoring results from second year

Figure 5 – Energy systems and metering points in boiler house 4

Figure 6 – Energy systems and metering points in boiler house 2